I__. - International Military Testing Association

tasks which meet the co-performance criterion for inclusion in clusters in which it was not
placed (potential core tasks), as well as tasks that are highly co-performed with all clusters
except the cluster under consideration (negatively unique tasks).
The experimental programs are as follow:
MODTYP - Just as the JOBTYP program automatically selects from a hierarchical
clustering of cases the “best” set of job types based on similarity of time spent across tasks,
the MODTYP (module typing) program selects from a hierarchical clustering of tasks the
“best” set of task module types based on task co-performance across cases. The term “best”
means that the evaluation algorithm initially optimizes on four criteria simultaneously (i.e.,
within-group homogeneity, between-group discrimination, group size, and drop in “between
overlap” in consecutive stages of the hierarchical clustering). After all stages of the clustering
. have been evaluated on these criteria, primary, secondary, and tertiary sets of mutually
exclusive task clusters are selected as first-, second-, and third-best representations of the
modular structure of the hierarchical clustering solution. The three sets of groups are then
input to another evaluation algorithm which computes super- and subgroup indices between
all pairs of groups in the primary solution within the same TPath range. Based on the
combined results of both evaluations, the sets of groups are revised. The final set of primary
groups is input to the TASSET and CORCAS programs to provide analytic and interpretive
data for each primary cluster of tasks. MODTYP output also reports the initial and final sets
of primary, secondary, and tertiary groups and their evaluation indices.
In addition to the data summaries of groups noted above, which can be very complex, a
graph of all final stages in TPATH sequence is generated to help the analyst understand the
relationship among the possible levels of clustering. An example of such a graph is shown
in Figure 2. In this case, Level 1 = primary group; Level 2 = secondary group; and Level
3 = tertiary group. By showing a different symbol for each level, the graph highlights the
most likely choices of groupings (task modules) for the analyst’s consideration. Used in
conjunction with the Task Cluster Diagram, this display provides a quick way for analysts to
make preliminary judgments as to the appropriate groups to select for further evaluation.
hIODTYP MODULE TYPING TEST RUN R-l Avionics Test Station, AFS 451X7 Page 13
Graph of All Final Stages in TPATH Sequence
1 289 578 867 1157
Stage TPATH Range Level + ____________--__---_ + ------------------- ---- + ___________-___-----___ + --------------
321 l- 72 2 __--__
384 l- 33 1 Xx
461 36 - 37 1 X
575 38- 40 1 X
766 42 - 43 1 X
342 46- 72 1 XxXx
333 l- 43 3 . . .
362 46- 63 3 . . .
401 64 - 71 3 . .
365 73 - 84 3 . .
469 73- 76 1 X
Figure 2. Example MODTYP Graph of All Final Stages in TPATH Sequence (AFS 45’1x7)
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